The information in this document is based on these software and
hardware versions:

All Cisco IOS® software versions

Cisco 3600 Series Routers

Cisco AS5800 Universal Access Server

Cisco 7200 Series Routers

Cisco 7500 Series Routers

Cisco 12000 Series Internet Routers

The information in this document was created from the devices in a
specific lab environment. All of the devices used in this document started with
a cleared (default) configuration. If your network is live, make sure that you
understand the potential impact of any command.

OIR was developed to enable you to replace faulty parts without
affecting system operation. When a card is inserted, power is available on the
card, and it initializes itself to start working.

Hot swap functionality allows the system to determine when a change
occurs in the unit's physical configuration, and reallocate the unit's
resources to allow all interfaces to function adequately. This feature allows
interfaces on the card to be reconfigured while other interfaces on the router
remain unchanged. The interrupt routine must ensure that the interrupt line has
reached a stable state.

The software performs the necessary tasks involved in handling the
removal and insertion of the card. A hardware interrupt is sent to the software
subsystem when a hardware change is detected, and the software reconfigures the
system as such:

When a card is inserted, it is analyzed and initialized in such a way
that the end user can configure it properly. The initialization routines used
during OIR are the same as those called when the router is powered on. System
resources, also handled by software, are allocated to the new
interface.

When a card is removed, the resources associated with the empty slot
must either be freed or altered to indicate the change in its
status.

Initializes all newly inserted interfaces and places them in the
administratively shut down state.

Brings all previously configured interfaces on the card back to the
state they were in when they were removed. Any newly inserted interfaces are
put in the administratively shut down state.

The only effect on the routing tables is that routes through a removed
interface are deleted, as are routes learned through that interface. The
Address Resolution Protocol (ARP) cache is selectively flushed, and routing
caches are completely flushed (this may also occur during normal operation of
the router, without OIR, and this is nothing to worry about).

If a card is reinserted into the same slot from which it was removed,
or if an identical card is inserted in its place, many of the control blocks
from the previous installation are reused. This is necessary due to the
implementation by Cisco IOS software of certain control blocks, and has the
benefit of saving the configuration from the previously installed card.

It is always safer to power down the router when you perform any
hardware changes, but here are some recommendations if you need to perform an
OIR. The system may indicate a hardware failure if you do not follow proper
procedures.

Insert only one card at a time; you must allow the system time to
complete the preceding tasks before you remove or insert another interface
processor. If you disrupt the sequence before the system completes its
verification, it can cause the system to detect spurious hardware
failures.

Insert the cards swiftly and firmly, but do not shove them
in.

If present, be sure to use the little plastic levers on the side of
the card to lock the card in.

If the OIR is successful, there is absolutely no need to schedule a
reload of the router.

If you get a LONGSTALL message after an OIR, or a CPUHOG during the OIR
process, but encounter no other problems, you may safely ignore those messages.
Detailed information about CPUHOG messages and their implication in OIR events
can be found in the
What
Causes %SYS-3-CPUHOG Messages? document.

A network module can only be replaced by a similar one (if OIR is
used). For example, an NM-12DM can be replaced only by another NM-12DM, and not
by an NM-6DM.

If a module has a T1/E1 interface, the T1/E1 controller should first
be disabled before the network module is swapped.

The new network module is functional only if the router has adequate
input and output (I/O) memory to support its operation (use the
2600/3600/3700 Memory Calculator
(registered customers only)
to find out the
memory requirements for your configuration).

You may experience an OIR-related error message on your Cisco 3600
Series Router, similar to this one:

Issue the
show
dial-shelf slot slot_number command
from the enable prompt on the router shelf and note the numeric value
associated with the type of feature board (in slot y) you
want to reset. In this sample output, the board type for slot 3 is 259:

Open a virtual connection to the Dial Shelf Controller (DSC) with
the dsip console slave
dsc_slot_number command. The value for
dsc_slot_number should be
either 12 or 13. The value depends on the slot number of the DSC that the
affected feature board belongs to. For example:

Issue the oir slot slot_number
remove command to remove the card using the software. The value
for slot_number should be the
slot number of the feature board on which you want to enable OIR (slot y in the
error message above).

The master RSP should normally not be removed while the system is
operating. However, if a Standby RSP is present, it takes over as per the
configured HA redundancy mode (for more information on this, refer to
Route
Processor Redundancy and Fast Software Upgrade on Cisco 7500 Series
Routers), but the traffic is interrupted. For Cisco 7500 Series routers,
the redundancy mode configured has no influence in case of an Online Removal of
the active RSP. Online removal of the active RSP causes all line cards to reset
and reload, which is equivalent to an RPR switchover, and results in a longer
switchover time. When it is necessary to remove the active RSP from the system,
first issue the switchover command to switch from
the active RSP to the standby RSP. When a switchover is forced to the standby
RSP before the previously active RSP is removed, the network operation benefits
from the continuous forwarding capability of Stateful Switchover (SSO), which
is supported in Cisco IOS software release 12.0(22)S and above.

Never insert a Versatile Interface Processor (VIP) without port
adapters; this configuration is not supported. Each unused interface processor
slot must contain an interface processor filler (which is an interface
processor carrier without a printed circuit board), to keep dust out of the
router and to maintain proper airflow through the interface processor
compartment.

OIR of port adapters is not supported, but you can remove the VIP
card completely, then add, remove, or replace the port adapter(s), and plug the
VIP card back in.

Note: In Cisco 7507/7507-MX or Cisco 7513/7513-MX routers with the high
system availability (HSA) feature active, online insertion and removal of any
interface processor in either CyBus might cause the slave RSP2 to reboot with a
bus error or a processor memory parity error. The master RSP recovers from this
event and issues a "cBus Complex Restart" message. Systems that are configured
with an RSP4 or an RSP8 as the system slave are not affected and do not
experience this problem. This issue is described in detail at
Field Notice: Cisco 7507 and Cisco 7513:
RSP2 HSA OIR.

Although the FlexWAN and Enhanced FlexWAN modules support hot swapping,
individual port adapters do not. To replace port adapters, you must first
remove the FlexWAN module from the chassis and then replace port adapters as
required.

If you replace an Engine type A line card with an Engine type B line
card, the line card configuration is not maintained across the swap, even if
the line cards are of the same media type. For example, if you replace a 4xOC12
POS Engine-2 line card with a 4xOC12 POS Engine-3 line card, all configurations
for the Engine-2 line card are lost and are not applied to the Engine-3 line
card.

The primary GRP should normally not be removed while the system is
operating. However, if a secondary GRP is present, it takes over. Make sure to
run a Cisco IOS software release that supports Route Processor Redundancy Plus
(RPR+). With RPR+, the secondary GRP is fully initialized and configured. This
feature dramatically shortens the switchover time if the primary GRP fails, or
if the primary GRP is removed from the system. More information on RPR+ is
available at
Cisco 12000 Series Internet Router Architecture: Route
Processor.

For Cisco 10000 and 12000 series Internet routers that are configured
to use Stateful Switchover (SSO), online removal of the active GRP
automatically forces a stateful switchover to the standby GRP. SSO is supported
since Cisco IOS software release 12.0(22)S. For more information, refer to
Stateful
Switchover.

The CSC can be removed and replaced, only if a second (redundant) CSC
is installed in the system. One CSC must be present and operational at all
times to maintain normal system operations. The switch to the redundant CSC
occurs in the order of seconds, during which time there can be loss of data on
some/all LCs.

On the 12406, 12416 and 12816, redundant CSCs should be removed only
after shutting them down first with the
hw-module
slot command, with the shutdown keyword.

On the 12406, 12416, and 12816, secondary CSC insertion causes
traffic interruption and spurious CRC error reports. Post 32S3 traffic loss
will not be seen

The SFC can be removed and replaced, without disrupting normal system
operations, only if a second (redundant) CSC is installed in the system (the
redundant CSC can function as either the CSC or the SFC).

On the 12406, 12410, 12416, 12810 and 12816, SFCs should be
physically removed only after they are first shutdown with the
hw-module slot command, with the shutdown keyword.
Failure to do this could result in a linecard crash.

On the 12406, 12410, and 12416, SFC insertion causes both traffic
loss and transient errors. Post 32S3 traffic loss will not be
seen

Note: The Cisco 12008, 12012, and 12016 can run with only one CSC and no
SFC if it uses only Engine 0 line cards. Other line cards are automatically
shut down.

Note: The 12404 has one board that contains all the CSC/SFC functionality.
For the 12404, there is no redundancy. The consolidated switch fabric cannot be
OIRed while the router is in function.